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1.
大块非晶Fe┐Al┐Ga┐P┐C┐B┐Si合金的热稳定性和磁性近年来发现了一系列具有大玻璃形成能力的多元系非晶合金,如Mg-Ln-(Ni,Cu)、Ln-Al-TM、Zr-Al-TM、Zr-Ti-Al-TM、Zr-Ti-TM-Be、Pd-Cu-Ni-P...  相似文献   

2.
1 INTRODUCTIONThebulkamorphousalloysofMg TM Ln ,Ln Al TM ,Zr Al TM ,Hf Al TMandTi Zr TMwerepreparedbyInoueandhisco workerssince 1990 [1] .Thec  相似文献   

3.
过渡金属Fe,Ni,Sc,Zr对2618铝合金组织和性能的影响   总被引:5,自引:2,他引:3  
配制了3种不同成分的Al-Cu-Mg-Fe-Ni-(Sc,Zr)实验合金,测量了合金在200℃的时效曲线及室温,300℃下的拉伸性能,采用金相显微镜、扫描电镜(能谱)和透射电镜观察了合金不同状态下的显微组织。结果表明:加入微量Sc和Zr后生成的一次A13(Sc,Zr)相可明显细化基体晶粒,二次析出的A13(S质点有明显的时效硬化效果,并且有利于合金中另一强化相S(A12CuMg)更均匀析出,从而提  相似文献   

4.
银—稀土氧化物触头材料的性能   总被引:10,自引:3,他引:10  
采用粉末冶金方法制备了新型银稀土氧化物触头材料 Ag/La2O3,它的密度为 9.71g/cm3-9.96g/cm3,硬度为760MPa-970Mpa,电阻率为2.25μΩ·cm-2.38μΩ·cm。利用扫描电镜(SEM)及能谱分析(EDS),对Ag/La2O触头材料的显微组织进行了分析,发现La2O3在Ag基体中呈极细小球状(直径<0.5μm)及不规则形(直径<3μm)2种形态均匀分布,经激光模拟电弧作用后,La2O3呈细小球状(<2.5μm)分布于Ag熔化区中,有助于减少Ag液的飞溅侵蚀。经与Ag/SnO2及Ag/CdO触头材料的主要物理、机械性能相对比,所研制的Ag/LaO3触头材料与后两者性能相近,因此有可能成为一种可替代 Ag/CdO的新型触头材料。  相似文献   

5.
王浩 Wong.  SP 《金属学报》1999,35(6):569-572
基于溅射-气体-聚焦(SGA)形成纳米金属颗粒的原理,提出了蒸发-气体-聚集(EGA)共沉积制备Co-Ag颗粒膜的新方法,并利用该方法制备了系列Co-Ag颗粒膜样品,TEM/ED分析表明;制备态样品Co颗粒被Ag原子所包裹,能有效地阻止颗粒的表面氧化与团聚,薄膜无需经过热处理即可形成Co与Ag的相分离,其结构为fcc-Co和fcc-Ag非均匀相多晶共存形态;与Co大块材料相比,薄膜中Co颗粒晶格常  相似文献   

6.
Sc对Al—Li—Cu—Mg—Zr合金组织与性能的影响   总被引:4,自引:0,他引:4  
蒋晓军  李依依 《金属学报》1994,30(8):A355-A361
研究了Sc对Al-Li-Cu-Mg-Zr合金的显微组织与拉伸性能的影响,结果表明,δ'(Al3Li)和S'(Al2CuMg)仍为含Sc合金中的主要强化相,Sc细化了合金的晶粒,降低了δ'颗粒的长大速度。促进了S'相的析出和均匀弥散分布,还使合金析出Al3Sc颗粒和Al3Li/Al3Sc复合析出相颗粒,这两种颗粒都有益于合金的性能,因此,加入Sc后合金表现出良好的强塑性配合。  相似文献   

7.
在聚乙烯醇(PVA)存在下,Ir(Ⅳ)与钼酸盐和丁基罗丹明B(BRB)形成离子缔合物。测定Ir的适宜条件为C_(HCιO4)=1.3mol/L,C_(MoO_4) ̄(2-)=1.1× ̄(-3)mol/L,C_(BRB)=3.8×10 ̄(-5)mol/L,PVA0.08%。离子缔合物的最大吸收位于570nm,摩尔吸光系数ε值为8.75×10 ̄5L·mol ̄(-1)·cm ̄(-1),至少可稳定一周,Ir量在0~2.5μg/25ml服从比尔定律,测定极限为8.3ng/ml(n=11),对于0.08μg/mlIr测定的相对标准偏差为2.8%(n=8)。考察了41种共存离子的影响,其他贵金属和Sb(Ⅱ)。Ge(Ⅳ)、Si(Ⅳ)干扰,需采用火试金分离。本法已用于某些岩矿和冶金中间产品中Ir的测定,结果满意。用平衡移动法测定缔合物的摩尔比为Ir:BRB=1:4,探讨了反应机理。  相似文献   

8.
汽车和战车中用钛的动向   总被引:9,自引:4,他引:9  
详细研究了通过机械合金化(MA)方法制备的Mg50Ni50-x-yMxNy(M,N=Al,Co和Si)系列非晶态贮氢合金的电化学特性。结果表明,该系列MA非晶合金的电化学活化容易,电化学容量高,其中Mg50Ni50合金的最大容量达500mA·h/g,约为晶态合金的10倍;但是它们的化学稳定性较差,容量的循环衰减速率达(10~60)mA·h/g·cycle。通过XRD分析,证实Mg-Ni基合金的性能衰退是由于其中的Mg在碱性溶液中被氧化所引起。  相似文献   

9.
MechanismofSecondaryElectronEmissionofCu-Al-MgAlloyPanQihan(潘奇汉)(GeneralResearchInsitituteforNon-ferrousMetals,Beijing100088,...  相似文献   

10.
DeterminationofNi,Ca,Mg,CuandPbinWolframbyInductivelyCoupledPlasmaAtomicEmisionSpectrometryWangChunmeiandZhangShuzhen(王春梅)(张淑...  相似文献   

11.
For the first time, Dy Sr AlO_4 of K_2NiF_4-type structure was synthesized. The parameters of Dy Sr AlO_4 elementary unit cell are determined as follows: a = 0.368(4) nm, c = 1.229(2) nm, V = 0.166(4) nm~3. The research of the complex aluminates Ln Sr Al O4(Ln = Nd, Gd, Dy) solid-state process demonstrated the change of the formation mechanism among Ln Sr AlO_4(Ln = Nd, Gd, Dy) series from Dy Sr AlO_4 oxide. The performed analysis provided a possibility to realize why chemists couldn't get Dy Sr AlO_4 for a long period of time.  相似文献   

12.
Series complexes of lanthanide hexacyanocobaltates (III), Ln[Co(CN)6]·nH2O (Ln=lanthanide ions; n=5,4) and yttrium hexacyanocobaltates (III) tetrahydrate were prepared, and the kinetics of the thermal dehydrations of these hydrates was studied. The dehydrations of Ln[Co(CN)6]·5H2O (Ln=La to Nd) took place through at least three stages, and those of Ln[Co(CN)6]·4H2O (Ln=Ce to Lu, and Y) through at least two stages. The each dehydration stage was found to be described as a first order reaction, F1. Activation energy for each stage was determined on the basis of thermogravimetry. The relationship between the activation energy for the each dehydration stages and the thermal stability of the series hydrates which was changing with the decrease of the ionic radii of lanthanide ions, was discussed.  相似文献   

13.
The lanthanide imidodiphosphinate complexes Ln(pip)3 (Ln = Ce, Nd, Tb, Ho) were prepared from the corresponding Ln[N(SiMe3)2]3 with [Ph2P(O)]2NH in a quantitative yield. X-ray single structure analysis of Ce(pip)3 has revealed that the lanthanide ion in these compounds coordinated by three bidentate [Ph2P(O)NP(O)Ph2] ligands and THF molecule. With respect to the organic light emitting diodes (OLED) application, the simple electroluminescent (EL) devices with a multilayer configuration ITO/TPD/Ln(pip)3/Yb, ITO/CBP/Ln(pip)3/Yb, ITO/TPD/Ln(pip)3/Alq3/Yb, ITO/TPD/Alq3/Ln(pip)3/Yb were fabricated. It was found that the lanthanide imidodiphosphinate complexes possess the hole-blocking and electron-transporting ability and it was also observed the exciplex emission between these complexes and TPD.  相似文献   

14.
TOPO has been applied to tiranium separation[l]. Some fundamental investigations for uranium extraction have also been well done [2, 3].However little data have been reported for theextraction of lanthanides with TOPO. Ceccoine[4] reported the lanthanides extraction withTOPO in chloroform at 25 C. Other authors stUdied the synergistic extraction of lanthanides byusing TOPO as a neutral adducts [5].For the past decade, the method using themolten paraffin wax as a diluent for the lanthan…  相似文献   

15.
Ab initio energetic calculations based on the density functional theory (DFF) and the projector augmented wave method (PAW) for determining the polymorphisms of lanthanide sesquioxides Ln2O3 (where Ln = rare-earth element, Y, and Sc), LnMO3 perovskites (where M = AI and Ga), and Ln2B207 pyrochlores (where B = Ti, Zr, and Hf) were reported. The relative lattice stabilities agreed well with the critically assessed results or the experimental results except the C-type Ln2O3 with a cubic structure, for which the calculated total energies were considerably more negative. With the increase of the Ln^3+-cation radius, the polymorphic structures showed a degenerative tendency. The tendencies and quantities of the enthalpies of formation of the ternary oxide ceramics synthesized from their constituent binary oxides reasonably agreed with the available experimental results, and valuable thermodynamic properties were afforded to the compound, for which no experimental data is available. The enthalpies of formation of both perovskites and pyrochlores tend to become more negative with the increase of the Ln^3+-cation radius.  相似文献   

16.
For the first time, DySrAlO4 of K2NiF4-type structure was synthesized. The parameters of DySrAlO4 elementary unit cell are determined as follows: a = 0.368 (4) nm, c = 1.229 (2) nm, V = 0.166 (4) nm3. The research of the complex aluminates LnSrAlO4 (Ln = Nd, Gd, Dy) solid-state process demonstrated the change of the formation mechanism among LnSrAlO4 (Ln = Nd, Gd, Dy) series from DySrAlO4 oxide. The performed analysis provided a possibility to realize why chemists couldn’t get DySrAlO4 for a long period of time.  相似文献   

17.
The synthesis of several members of the series LnSrVO4 can be achieved by hydrogen reduction of mixtures of Ln2O3, SrCO3 and V2O5 or SrCO3 and LnVO4 at 1200 °C for 24 h. The series exists from lanthanum to terbium inclusive. The range of existence is discussed in terms of the ratio of radii of the structure fields and the large cation size mismatch ratios. Crystal structures were refined from powder neutron diffraction data for Ln La, Ce Pr and Nd. Cell constants are reported for all members from X-ray Guinier data. All compounds are isostructural with K2NiF4, I4/mmm. Magnetic susceptibility data from 4.2 K to 300 K are described. It is possible that a local moment of about 2.6 β per V3+ exists for Ln Ce, Pr and Nd but Ln La represents a different case.  相似文献   

18.
Glass transition temperatures Tg and Raman spectra of KPO3·Ln(PO3)3 (Ln=rare earth ion) glasses were measured for all rare earth members (except Pm). From the series behavior of the Tg and Raman data, it is concluded that the coordination number around rare earth ions changes, probably from nine to eight, in the middle of the rare earth series.  相似文献   

19.
The interaction between neutral, lanthanide bis(tetra-15-crown-5-phthalocyaninate) complexes Ln[(15C5)4Pc]20, (Ln = La, Tb, and Tm) and potassium bromide, picrate, or tetraphenylborate in chloro-form-acetonitrile solutions is studied using the spectrophotometric titration. The architecture of the supramolecular aggregates formed is shown to depend on the size of the lanthanide ion introduced into crown-phthalocyaninate and the nature of potassium salt anion.  相似文献   

20.
The heteropoly complexes K12[Ln(GeW9Mo2O39)2] · nH2O (Ln = La, Ce, Pr, Nd, and Sm) were prepared for the first time and characterized by chemical analysis, infrared (IR) spectrum, ultraviolet (UV) spectrum, X-ray powder diffraction, and thermal analysis. IR, UV spectra, and X-ray powder diffraction studies show that the structure of the heteropoly complexes is a square antiprism consisting of eight oxygen atoms of two GeW9Mo2O398-, heteropolyanions and a lanthanide ion. The thermostability of heteropoly complexes is lower than that of saturated Keggin structure dodecatungstogermanate.  相似文献   

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